Symmetric leading edge device and method to delay flow separation

Abstract

A vertical tail for use with an aircraft or other form of mobile platform. The vertical tail includes a main element which is fixedly secured to the mobile platform, and a leading edge element that is movably secured to the main element. The cross section of the leading edge element is symmetric about the cruise chord line of the tail. The leading edge element can be pivoted and/or extended to create a gap with the main (fixed) element. The movable leading edge element is used to increase the maximum yawing moment provided by the vertical tail. The maximum yawing moment is increased when air flow is incident from either side of the vertical tail.

1. An airborne mobile platform comprising:
 a vertical tail; 
 said vertical tail including a leading edge element and a main element, the leading edge element being movable linearly in accordance with a longitudinal centerline of the main element between an extended position and a retracted position to change a distance of a gap between the leading edge element and the main element, and to thus increase a maximum aerodynamic yawing moment provided by the vertical tail. 
 
     
     
       2. The airborne mobile platform of  claim 1 , wherein movement of said vertical tail increases said maximum yawing moment for both positive and negative sideslip angles. 
     
     
       3. The airborne mobile platform of  claim 1 , wherein said leading edge element features a shape that is symmetric about a cruise cord-line of the vertical tail. 
     
     
       4. The airborne mobile platform of  claim 1 , wherein said leading edge element is pivotally supported from said main element. 
     
     
       5. The airborne mobile platform of  claim 1 , wherein said leading edge element is further pivotally movable relative to said main element. 
     
     
       6. The airborne mobile platform of  claim 1 , wherein said vertical tail includes a pivotally moveable rudder that is controlled with movement of said leading edge element. 
     
     
       7. The airborne mobile platform of  claim 5 , wherein said tail further comprises a pivotally mounted rudder. 
     
     
       8. The airborne mobile platform of  claim 7 , wherein said rudder is pivoted in connection with movement of said leading edge element. 
     
     
       9. The airborne mobile platform of  claim 1 , further including an actuator for moving said leading edge element. 
     
     
       10. The airborne mobile platform of  claim 9 , wherein said actuator comprises a hydraulic actuator. 
     
     
       11. The airborne mobile platform of  claim 9 , wherein said actuator comprises an electromechanical actuator. 
     
     
       12. The airborne mobile platform of  claim 9 , wherein said actuator comprises a pneumatic actuator.